Hi Mike,
that is a very sad and tragic story.
Most inquests were reported in the newspaper. If you have an idea of when Mary Ann died you will be able to get a copy of the inquest from the local library.
Like you I am in Austraila and managed to get two inquests for 1882 & 1901 - from Tameside Library. They didn't charge me a cent - just posted the photo copies of the newspaper.
Both reports are lengthy and I was amazed at the details given. I even know what the family had for supper.
Hopefully you know the area where Mary Ann lived so if you contact the local library and give them the details they can check for the newspaper report.
Hope you are as lucky as I was.
Regards
Darcy